Unknown Lab Report.docx - Zofia Chrobak Professor Sandra...

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Zofia ChrobakProfessor Sandra GibbonsBIO 119-35014 December 2017Bacterial Unknown Lab ReportAbstract:The main purpose of this lab is to perform a multiple number of morphological tests tocollect information about a certain unknown bacterium and then use it to identify the organism. ANutrient broth culture consisting of an unknown bacterium was collected. In addition to onemotility tube and two NA (Nutrient Agar) slants, each student needed one of each of thefollowing mediums: Citrate slant, Glucose broth, Lactose broth, Sucrose broth, SIM (SulfurIndole Motility) tube, TSB (tryptone) broth, Urea slant, Mannitol Salt plate, Starch/Milk splitplate, and a EMB (Eosin Methylene Blue) plate. Each medium was inoculated with thebacterium using good aseptic technique and then they were according incubated. The mainresults are as follows: rod shape, negative for Gram stain, Spore stain, and Acid-Fast stain,opaque colored growth, growth on the EMB, no salt or fermentation on the MSA plate, negativefor hydrogen sulfide, positive for glucose with no ability to make gas, negative for sucrose,lactose, indole, and urea, positive for casein and citrate, and finally positive for motility. It wasconcluded the bacterium is Gram-negative because it stained pink and there were visible rods.Based on the results of the different characteristics and tests, it is safe to conclude that theunknown bacterium isPseudomonas aeruginosa.Introduction:There are two main approaches taken to identify an unknown bacterium. First, it can bedone by observing the morphological characteristics of an unknown microbe. This approach issimple but limited. Because of this, biochemical characteristics are more commonly used for
bacterial identification. They provide more precise information because they are based on abacterium’s metabolism, which is all the chemical reactions that occur in a cell. Metabolismdirectly defines bacteria as the diversity seen derives from a bacterium’s ability to producedifferent enzymes. The lab measured several morphological and physiological criteria, such ascell shape and colony characteristics, to allow one to identify unknown bacteria. Other moreadvanced tests included fermentation, reduction, hydrolytic, and biochemical reactions. It issuspected that when following the appropriate procedure, all the morphological and culturalcharacteristics will be identified and used to conclude the name of the bacterium present. Based

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Term
Spring
Professor
StevenDroho
Tags
Bacteria, indole

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